<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="./style.css">
    <title>Document</title>
</head>
<body>
    <!-- 水滴型 -->
    <div class="container1">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>

    <!-- 圆球旋转 -->
    <div class="container2">
        <div style="--b: 1"></div>
        <div style="--b: 2"></div>
        <div style="--b: 3"></div>
        <div style="--b: 4"></div>
        <div style="--b: 5"></div>
    </div>

    <!-- 条状伸缩 -->
    <div class="container3">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>

    <!-- 移动方块 -->
    <div class="container4">
        <div></div>
        <div></div>
        <div></div>
    </div>
</body>
</html>